World's Tallest Building Causing Earthquakes?

IZ Reloaded writes "A geologist thinks that the increase in the number of earthquakes in Taiwan is due to Taipei 101, the world's tallest building. CNN reports: 'Lin said Taipei 101 weighed 700,000 tons and estimated stress from vertical loading on its foundation at 4.7 bars, of which some would be transferred to the earth's upper crust due to extremely soft sedimentary rocks beneath the Taipei basin. If a fault is about to crack, then a little pressure can trigger an earthquake. It's like the last straw that breaks the camel's back.'" More from The Guardian.

Comments

Tallest != Largest

[RedWizzard]

Bit of a misleading headline. Taipei 101 may be the world's tallest building (by some definitions), but it's not the largest. The Pentagon is larger by floor area and several buildings are much larger by volume. Wikipedia has more.

Re:Tallest != Largest

[cjanota]

Height has everything to do with potential energy, at least from the gravity point of view. PE=mgh But having more potential energy has nothing to do with the pressure on the ground. It is a static situation. Potential energy would only come into play if the building were to fall down.

Re:it may be tall but its not the "largest"

[ari_j]

List of world's tallest structures. The tallest structure is a TV mast in eastern North Dakota. Taipei 101 is the tallest skyscraper unless you count the masts on top of the Sears Tower, and then that one wins out. See this article for more details.

The Pentagon is the world's largest office building. The largest building by volume is the Boeing plant that manufactures 747's, 767's, and 777's in Washington. The NASA Vehicle Assembly Building is second or third.

But as far as pressure on the bedrock, I would have no problem accepting that Taipei 101 tops the list. It is an extremely big skyscraper on a relatively very small footprint.

Induced Seismicity

[FuzzyBad-Mofo]

This is called induced seismicity, and I really would be surprised if a mere 700,000 tons could trigger it. It's a real problem with dams and the enormous weight of water in their reservoirs, and no doubt keeps the project managers of the Three Gorges Dam awake at night (the dam is built on a fault line).

Re:Induced Seismicity

[cluckshot]

Inducing earthquakes is a long known process. It was sufficiently known by the 1930's that the US TVA anticipated it during the construction and operation of its large dams and lakes. These have since happened pretty much as expected. The US War Department (Yes -- War Department - before WW2) had built Wilson Dam at Florence, Alabama and finished it in 1926. The dam has kicked off up to 4.0 quakes and frequent in the 3.0 to 3.5 range since it was completed. It occurs every few years. The US TVA Guntersville Dam and lake causes quakes in the order of 2.5 to 3.5 with some frequency.

As another poster noted the 3-Gorges dam in China is anticipated to cause quakes. The size here is expected to cause quakes in the order of 7 to 8 on the Richter Scale. It has already caused numerous quakes in the order of 5.5 or so. There have been quakes upwards of that as well.

Hydro pool events are often discounted by some parties because rivers are always found adjacent to faults. This is because rivers tend to flow in the crack of a fault. The problem here is that the faults don't produce the large quakes until the lakes are added. The process clearly increases the quake intensity and frequency in the area.

The masses of water and hydrocarbon recovered from Coal Gas fields in Alabama have shown frequent quakes in the order of 2.0 to 3.5 happening in a zone which didn't have any quake frequency before. In South Alabama in the massive Natural Gas extraction efforts there the extraction of brines and natural gas have resulted in frequent quakes where the USGS says they expect few if any ever to occur. These have been in the range from 4.9 down to 2.5. The largest quake in Alabama history happened during Natural Gas well proving at the Little Rock Gas Field in Escambia County near Atmore. It was a 4.9. The Power River Coal Gas development will have quakes frequently up to 5 or 6 on the scale from this. Add these to the natural risk in the area and serious problems are expected.

One cannot say for sure what affect or effect happened at Ache in Sumatra in the quake/tsunami there but massive Natural Gas proving (Well blowing) operations were under way at the time that produced natural gas flares with fire upwards of 600 square miles in size at the time. Similar operations were under way in the region of Alaska at the time of the 1964 quake there.

It is absolutely sure that mankind can at least trigger a latient earthquake with large structures and large mining operations. It may be that such events are even partially caused by such activity.

To be fair, a large building might cause a quake as the earth adjusts to the new stress levels. It is a process that in time will settle down as there is no real dynamic change in the building's mass except the commuters. This is unlike hydro pools which change dynamically or like oil/gas operations which cause massive dynamic changes in the earth. Oil/Gas operations cause such massive dynamic changes in areas that they actually are larger than even the 3 Gorges Dam in mass changes in some areas. The withdrawal of 200 to 300 times in brine of the hydrocarbon extraction causes these operations to be the largest mass changes man is causing on the earth. Pressure changes in these formations represent some of the largest forces on the planet. Latient pressures in field like Petronius near Alabama reach up to 50,000 psi.

Re:Nature will work it out

[big tex]

One of the unique features of manhattan (actually, most of NYC, esp. the Bronx) is lots of bedrock, real close. When we were tunneling for the 3rd water tunnel, the rock was hitting 16,000psi - 20,000psi, if I remember correct. That's so hard that it's unbelievable.

You don't drive piles in manhattan, shit just bottoms out on rock so fast it hurts. Spread footings, caissons with rock sockets, that's what you use.

the end result is that the load is distributed so far it doesn't matter.

Re:Nature will work it out

[CODiNE]

We can't have a big impact on nature? Okay since you mentioned the New Orleans levees, here you go.
http://magma.nationalgeographic.com/ngm/0410/featu re5/
By screwing with nature we caused all that damage during Katrina, that article was written a year ago. It had been known for decades that we'd been screwing up the whole region and eventually it was gonna come back and get us. Naaah... we can't really have much of an impact... Whoah! Hey where'd the Aral Sea go?
http://unimaps.com/aral-sea/index.html

Mods, why is this guy a 5? Induced Seismicity is explained several times in other posts... are you too busy trying to protect your "We can't hurt the earth" biases?